• DOI:10.1088/1475-7516/2017/11/026
• Corpus ID: 119453054

Anisotropic inflation with a non-minimally coupled electromagnetic field to gravity

@article{Adak2016AnisotropicIW,
  title={Anisotropic inflation with a non-minimally coupled electromagnetic field to gravity},
  author={Muzaffer Adak and {\"O}zg{\"u}r Akarsu and Tekin Dereli and {\"O}zcan Sert},
  journal={Journal of Cosmology and Astroparticle Physics},
  year={2016},
  volume={2017},
  pages={026 - 026}
}

• M. Adak, Özgür Akarsu, +1 author Özcan Sert
• Published 10 November 2016
• Geology
• Journal of Cosmology and Astroparticle Physics

We consider the non-minimal model of gravity in Y(R) F2-form. We investigate a particular case of the model, for which the higher order derivatives are eliminated but the scalar curvature R is kept to be dynamical via the constraint YRFmnFmn =−2/κ2. The effective fluid obtained can be represented by interacting electromagnetic field and vacuum depending on Y(R), namely, the energy density of the vacuum tracks R while energy density of the conventional electromagnetic field is dynamically scaled with the factor Y(R)/2. We give exact solutions for anisotropic inflation by assuming the volume scale factor of the Universe exhibits a power-law expansion. The directional scale factors do not necessarily exhibit power-law expansion, which would give rise to a constant expansion anisotropy, but expand non-trivially and give rise to a non-monotonically evolving expansion anisotropy that eventually converges to a non-zero constant. Relying on this fact, we discuss the anisotropic e-fold during the inflation by considering observed scale invariance in CMB and demanding the Universe to undergo the same amount of e-folds in all directions. We calculate the residual expansion anisotropy at the end of inflation, though as a result of non-monotonic behaviour of expansion anisotropy all the axes of the Universe undergo the same of amount of e-folds by the end of inflation. We also discuss the generation of the modified electromagnetic field during the first few e-folds of the inflation and its persistence against to the vacuum till end of inflation.